Dementia is a term applied to many disorders that are characterized by a gradual decline in intellectual functioning exceeding the normal aging process. The diagnosis dementia does not imply any specific etiology, but applies to a number of disorders including Alzheimer's disease (AD) (the most frequent cause of dementia), Vascular dementia and Pick's disease. Long-term use of alcohol is also associated with deficits in intellectual functioning in a high percentage of elderly individuals. The term "Alcohol Dementia" has been used to describe this disorder which is clinically thought to be reversible, at least in part, if the individual remains abstinent. Alcohol Dementia has been dissociated from Korsakoff's syndrome which is considered to be a focal amnestic disorder rather than a dementia. Within the population of elderly individuals who are conjointly demented and have a history of alcohol abuse (but not Korsakoff's syndrome) it is clinically difficult to differentiate those individuals whose dementia is caused by AD from those whose dementia is caused by significant alcohol abuse. This difficulty has undoubtedly contributed to the lack of research on Alcohol Dementia. In fact, it is not clear that Alcohol Dementia exists as a separate entity that is clearly distinguishable from AD or Vascular dementia. Given the overlapping presence of AD, Vascular dementia and Alcohol Dementia in the elderly the likelihood of misdiagnosis is high. Being able to differentiate AD and Alcohol Dementia is not only of theoretical interest but clearly has major practical and public health significance as the prognosis for Alcohol Dementia is likely very different from that for Alzheimer's disease. A five-year cross-sectional and prospective study is proposed to validate the taxonomy of Alcohol Dementia, characterize the cognitive deficits associated with the disorder, differentiate the disorder from AD, and document the natural history. In the cross-sectional component of this FIRST proposal we will characterize and delineate the neuropsychological features which distinguish Alcohol Dementia from AD. In the longitudinal component the progression of cognitive deficits will be contrasted in abstinent and nonabstinent elderly alcoholics and individuals with AD. Comparisons between the alcoholic groups and the AD group, together with evaluation of cognitive changes over the two year follow-up will enable; 1) discrimination of alcoholics exhibiting Alcohol Dementia; 2) delineation of cognitive profiles associated with Alcoholic Dementia; and 3) investigation of the validity, specificity, etiology and natural history of the taxonomic category of Alcoholic Dementia and the long-term implication of abstinence on the disease process.